Abstract: Effect of fertilization and spraying paclobutrazol on plant height and leaf age of rice seedling were studied. The results showed that fertilization could increase but spraying paclobutrazol decrease the plant height, and both two could increase the leaf age. Among which, applying only fertilizer had the best effect of increasing plant height; applying fertilizer and applying 300 mg/kg paclobutrazol (drug/water) at period of 1 leaf with 1 bud had the best effect of increasing leaf age, whereas non-fertilization and applying 300 mg/kg paclobutrazol at period of 1 leaf with 1 bud had the best effect of depressing plant height.